1. Field of the Invention
The present invention relates to a stitchbonded nonwoven fabric having a fibrous layer and spaced apart, interconnected rows of bulkable thread stitches. In particular, the invention concerns such a fabric in which the bulkable threads are non-elastomeric and amount to 25 to 60% of the total weight of the fabric. The fabric has high tear resistance and is especially suited for use in industrial applications, such as tarpaulins, geotextiles, coated fabric, automobile airbags, banners, furniture decking, fabric liners, apparel interliners and the like.
2. Description of the Prior Art
Stitchbonded fabrics are known in the art. Such fabrics are often made by multi-needle stitching of a fibrous layer with one or more stitching thread systems. The stitching forms spaced apart, interconnected rows of stitches, usually at a spacing in the range of 2 to 8 rows per centimeter. In each row, stitch spacing is in the range 2 to 10 stitches per cm. Typically, the stitchbonded fabric is made with a fibrous layer of staple fibers of textile decitex (e.g., 1 to 15 dtex), and ordinary stitching threads (e.g., of nylon, polyester, acrylic or natural fibers). Stitchbonding of fibrous layers of continuous filament webs is also known, as for example from Product Licensing Index, Research Disclosure, page 30, (June 1968).
Use of elastic or bulkable stitching thread for making bulky and/or stretchy stitchbonded fabrics is a more recent development in the art. Such fabrics are disclosed, for example, in my earlier U.S. Pat. Nos. 4,876,128, 4,773,238, 4,737,394 and 4,704,321. Usually, the stitched fabric is allowed to shrink and gather immediately after the multi-needle stitching operation to effect a very large reduction in fabric area. A fibrous layer of polyolefin plexifilaments stitchbonded with a bulkable stitching thread which amounts to a maximum of 40% of the total weight of the fabric is disclosed in the patents, but much lower yarn contents are specifically disclosed in the examples. The bulkable stitching thread usually is an elastic yarn that preferably comprises spandex elastomeric filaments wrapped with nylon yarns and is capable of elongating and retracting in the range of 100 to 250%. Bulkable stitching threads of yarns that are heat shrinkable, textured, or otherwise stretch yarns, made from polyester, nylon, or other polymers, are disclosed to function in a similar manner to spandex yarns but with less elongation and contraction.
Stitchbonded nonwoven fabrics made with bulkable yarns usually have high specific volume (i.e., bulk) and high tensile strength and are suited particularly for use as insulation fabrics, special elastic fabrics, dust wipes, and the like. However, such stitchbonded fabrics, unless of heavy weight, usually lack the high tear resistance desired for industrial fabrics.
It is an object of this invention to provide a stitchbonded nonwoven fabric that has high tear resistance and is suitable for use as an industrial fabric.